High temperature nickel base alloy



United States Patent I 2,948,606 HIGHTEMPERATURE NICKEL BASE ALLoy Rudolf H. Thielemann, Palo Alto, Calif., assignor to Sierra Metals Corporation, a corporation of Delaware No Drawing. Filed May 31, 1957, Ser. No. 662,577 7 6 Claims. (Cl. 75-171 This invention relates to a nickel-chromium-cobalt base metal alloy, particularly to one such alloywhich includes alloying metal additives which make the resulting alloy corrosion resistant and of great mechanical work strength at temperatures above 1500 F.

Important features of the alloy of this invention are that it may be hot Worked, is highly resistant to oxidation and other forms of corrosion and possesses great mechanical work strength at temperatures up to between about 1600 F. and 2000 F. As a result this alloy may be used as blades, vanes, and other parts of high temperature'gas turbine engines. Other important uses 'ofthe alloy of this invention are as exhaust valves and manifolds in internal combustion engines, in heat exchangers, and as linings for retorts and container vessels used in the chemical and metallurgical industries. a a

The prior art, nickel and/or cobalt base metal alloys which have been used as blades, vanes, and other parts of high temperature gas turbine engines, have a maximum operating temperature of about 1500 F. For example, a common nickel-cobalt base metal alloy which incorporates molybdenum as a constituent is for all practical purposes non-utilizable as a structural member in a gas turbine engine if the metal temperature is above 1500 F. The oxidation resistance of such an alloy fails above 1500 F.

Since the alloy of this invention when used as a blade or vane in a high temperature gas turbine engine can be operated at markedly higher temperatures than was possible heretofore, the performance of the gas turbine engine is improved, in that the total thrust is increased and the amount of fuel consumed per pound of trust is decreased.

The metal alloy of this invention is comprised by weight of about: 15 to 25 percent chromium, to 30 percent cobalt, 0.5 to 4 percent titanium, 2 to 5 percent aluminum, 1 to 5 percent of columbium or tantalum or mixtures thereof, 5 to 11 percent tungsten, and the balance, essentially nickel.

An alloy having the above composition is particularly resistant to oxidation and has high strength at elevated temperatures above 1500 F., so as to be suitable for use in forming cast liners for retorts and container vessels used in the chemical and metallurgical industries.

When the alloy of this invention is to be used as blades or vanes or other parts in a high temperature gas turbine engine, I have found that if the hardening elements in the alloy, i.e., the tungsten, aluminum, titanium, and columbium or tantalum or mixtures thereof, are so chosen that the sum of (a) the percentage by weight of tungsten, plus (b) one-and-a-half times the percentage by weight of columbium, or tantalum or mixtures thereof, plus (0) two times the percentage by weight of aluminum, plus (0!) four times the percentage by weight of titanium is equal to a number within a range of about 20 to 30, then the alloy of this invention is capable of being hot worked and has a life to rupture strength (rupture life) in exfl ce cess of 100 hours under a load of 25,000 pounds per square inch at 1700 F. 7 The numericalsum of (a), (b), (c) and (d) above shall hereafter be referred to as the equivalent hardening factor.v This factor is applicable only if the base constituents ,of the alloy (the nickel, chromium andco balt) are present in the proportions. set forth above. A preferr'edrange of the equivalent hardening factor isbe: tween23 and 28; When the alloy of this invention meets the equivalent hardening factor limitation, the desiredhigh temperature creep strength 'of the alloy is achieved. If the alloy 'exceeds the equivalent hardening factor limit of 30, hot working of the alloybecomes very diflicult and for all practical purposes the alloy cannot be shaped into desired forms. Thus, use [of the formula insur'esthat an alloy having thejdesired high temperature strength can be satisfactorily hot worked. 3 f To achieve the desired properties, the impurities in the alloy must be held to the'following limits by weight. The carbon content in the final alloy should be no morethan about 0.5 percent; the oxygen content, no more than about 0.3, percent as determined by an increase on ignition technique; the.ni trogen content, no more than about ).5, percent; the hydrogen content, no more than about 0.001 percent; the lead content, no more than about 0.001 percent; andthe iron content, no more than about 5 percent.

' In addition, no more than about .5 percent of the come bined elements calcium, magnesium, cerium, and other rare earth metals should be present.

In orderto further improve workability of the alloy, particularly when in the form of a large cast ingot, a small quantity of zirconium and/or boron, or compounds there-i of, such as zirconium Iboride'may be added to the alloy of thisfinvention. As, a result, large ingots. can,be,mo're' readily formed into sheet and other forms, than is possible without the addition of zirconium and/or,boron..'...To achieve this effect, an amount of zirconium up to about 0.2 percent by weight and/or an amount of boron up to about 0.1 percent by weight is incorporated in the --alloy ofthis invention.

Following are. examples of'the preparationand ,test results of the nickelchromium-cobalt base-metal alloy, ofthis invention: C

EXAMPLE 1 A 10 pound ingot of a nickel-chromium-cobaltbase metal alloy composition containing 20 percent of 611mm: him, 15 percent of cobalt,one percent of titanium, 2 percent of aluminum, 1.5 percent of tantalum, IOpercent of tungsten, and the balance, substantially all nickel, all by weight, was prepared by melting a nickel, chromium and cobalt mix in a magnesia crucible under avacuum condition of about 10. microns and'heldin a molten state until outgassing was essentially completed. Carbon was then added to the molten mix to permit outgassing of the dissolved oxygen in the form of cQ and CO. Ten perf cent of tungsten, 1.5 percent of tantalum, 2 percent of aluminum and one percent of titanium were added to the molten metals in theorder named, following which the resulting molten metal alloy was cast under a vacuum of about 10 micronsinto a 10 pound ingot inold and allowed to solidify under vacuum. 7

Test bars A inch diameter and 3 inches long) were fabricated from this ingot by hot working procedure and then heat treated in the usual fashion by solution treating and aging which consisted of heating the test bars to a temperature of about 2150 F. and holding at this temperature for about one hour, air cooling the bars, and then heating the bars at a temperature of about 1600F. for about 8 hours, followed by air cooling. a i 'The 'testbars-of this example had a rupture life'of about 108 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 2 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 1.5 percent of titanium, 2.5 percent of aluminum, 1.5 percent of columbium, 10 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 223 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 3 A 10pound ingot and test bars of the same dimensions as set forth in. Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3 percent of aluminum, 1.5 percent of tantalum, 8 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 268 hours under a load of 25,000 pounds per square inch at a temperature of 1700" F. in air.

EXAMPLE 4 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium,.l5 percent of cobalt, 1.5 percent of titanium, 2.5 percent of aluminum, 2.0 percent of tantalum, 8.0 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 167 hours under a load of 25,000 pounds per square inch at a temperature of 1700" in air.

EXAMPLE 5 A pound ingot and test bars of the same dimensions as set forth .in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, percent of cobalt, 2 percent of titanium, 3 percent of aluminum, 1.5 percent of columbium, 8 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 273 hours under a load of 25,000 pounds per square inch at a temperature of 1700" F. in air.

EXAMPLE 6 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing '20 percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3.5 percent of aluminum, 1.0 percent of tantalum, 10 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 366 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 7 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3.5 percent of aluminum, 1 percent of tantalum, 10 percent of tungsten, 0.2 percent of zirconium, and the-bal- A ance, substantially all nickel, all by weight, were prepared in the same manner as set forth in Example 1, except that the zirconium was added immediately following the addition of titanium to the molten metals.

The test bars of this example had a rupture life of about 362 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 8 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3.5 percent of aluminum, 1 percent of tantalum, 10 percent of tungsten, .1 percent of boron, and the balance, substantially all nickel, all by weight, were prepared in the same manner as set forth in Example 1, except that the boron was added immediately following the addition of titanium to the molten metals.

{The test bars of this example had a rupture life of about 365 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 9 A 10 pound ingot and test 'bars of the same dimensions as set forth in Example 1 of a nickel-chromium'cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3.5 percent of aluminum, 1 percent of tantalum, 10 per cent of tungsten, .1 percent of zirconium, and the balance, substantially all nickel, all by weight, were prepared in the same manner as set forth in Example 1, except that the zirconium was added immediately following the addition of titanium to the molten metals.

The test bars of this example had a rupture life of about 365 hours under a load of 25,000 pounds per square inch at a temperature of 1700" F. in air.

EXAMPLE 10 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3.5 percent of aluminum, 1 percent of tantalum, 10 percent of tungsten, .05 percent of boron, and the balance, substantially all nickel, all by weight, were prepared in the same manner as set forth in Example 1, except that the boron was added immediately following the addition of titanium to the molten metals.

The test bars of this example had a rupture life of about 360 hours under a load of 25,000 pounds per square inch at a temperature of 1700" F. in air.

EXAMPLE 11 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 2 percent of titanium, 3.5 percent of aluminum, 1 percent of columbium, 10 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 356 hours under a load of 25 ,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 12 by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

. The test bars, of this example had a rupture lifeof about 374 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 13 p A pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, percent of cobalt, 3 percent of titanium, 2

percent of aluminum, 3 percent of columbium, 7 percentof tungsten, and the balance substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture; life of about 408 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 14 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing percent of. chromium, 15 percent of cobalt, 2 percentof titanium, 4.5 percent of aluminum, 4.5 percent of tantalum, 6 percent,

EXAMPLE 15 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 3.75 percent of titanium, 3 percent of aluminum, 4 percent of columbium, 5 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 507 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 16 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, .5 percent of titanium, 2 percent of aluminum, 1 percent of tantalum, 9' percent of tungsten, and the balance, substantially all nickel, all 'by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 24.5 hours under a load of ,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 17 A 10 pound ingot and test bars of the same dimensions EXAMPLE 18 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 1 percent of titanium, 2

percent of aluminum, 1.5 percent of tantalum, 5 percent of tungsten, and the balance, substantially all nickel, all

pounds per by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

'The test bars of this example had a rupture life of about 14.5 hours under a load of 25,000 pounds per square inch at a temperature of 1700" 'F. in air.

EXAMPLE. 19

A 10 pound ingot and test bars of the same dimensions as set forth in: Example 1 ofa nickel-chromium-cobalt base metal alloy. composition. containing 20 percent of chromium;-15 percent of;coba;lt, 1 percent oftitanium, 2 percent of aluminum, 2 percent of columbium, 9 percent of tungsten, and the balance, substantially all nickel,

all by-weight, were prepared and the bars heat treated in thejsanije manner as set forth in Example 1.1 v

The test bars'of this example had a rupturelife of about 42 hoursunder a load of 25,000 pounds per square 1 inch at a temperature of 1700 F. in air.

I 10 pound ingot and test barsof the samedimensions assetforth in Example 1 of a nickel-chromium-cobalt EXAMPLE 20 base metal alloycomposition containing 15 percent of chromium, 30 percent of cobalt,2 percent of titanium, 3 percent of aluminum, 1.5 percent of tantalum, 8fpercentof tungsten, and the balance, substantially all nickel,

[all by weight,"were prepared and the bars liefatjtreated in the same manner as set forth inExample 1.-

. The 'test bars of this example had a rupture life of. about 271 hours under a load of 25 ,000. pounds per square inch at a temperature of l700, F. in air.

EXAMPLE 21 A 10 pound ingot and test bars of the same dimensions as set forth'in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 25 percent of chromium, 5 percent of cobalt, 2 percent of titanium, 3 percent of aluminum, 1.5 percent of tantalum, 8 percent of tungsten, and the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 267 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 22 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 17 percent of" chromium, 10 percent of cobalt, 4 percent of'titanium, 2'

about 466 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in'air.

EXAMPLE 23 A 10 pound ingot and test bars of the same dimensionsas set forth in Example 1 of a nickel-chromium-cobalt base metal alloy composition containing 20 percent of chromium, 15 percent of cobalt, 1 percent of titanium,

5 percent of aluminum, 5 percent of columbium, 8 per cent of tungsten and'the balance, substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 425 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in air.

EXAMPLE 24 A 10 pound ingot and test bars of the same dimensions as set forth in Example 1 of a nickel-chromium-cobaltj base metal alloy composition containing 20 percent ofchromium, 15 percent of cobalt, v1 percent of titanium} in the' 2 percent of aluminum, 2 perc'entof columbium, 11 per cent of tungsten, and the balance substantially all nickel, all by weight, were prepared and the bars heat treated in the same manner as set forth in Example 1.

The test bars of this example had a rupture life of about 172 hours under a load of 25,000 pounds per square inch at a temperature of 1700 F. in. air.

8 the percentage of titanium equals a number within the range of about 20 to about 30.

2. A high temperature, high strength nickel-chromium-cobalt base metal alloy composed by weight of about 15 percent to 25 percent chromium; 5 percent to 30 percent cobalt; 0.5 percent to 4 percent titanium; 2 percent to 5 percent aluminum; 1 percent to 5 percent of a metal Table Example No. Cr Ti T5 b W Zr B N1 E.H.F.

20 15 1 2 1.5 20.25 108 20 15 1 5 2.5 1.5 23.25 22s 20 15 2 a 1.5 24.25 258 20 15 1 5 2.5 2 22 157 20 15 2 3 1.5 24.25 273 20 15 2 3.5 1 25.5 355 20 15 2 3.5 1 25.5 552 20 15 2 2.5 1 25.5 355 20 15 2 5.5 1 B51 25.5 355 20 15 2 3.5 1 51. 25.5 350 20 15 2 5.5 1 25.5 355 20 15 2 5 5 4 5 B51. 27 374 20 15 3 2 5 7 B51. 27.5 40s 20 15 2 4.5 4.5 5 B51. 29.75 493 20 15 5 75 4 3 B51. 30 507 20 15 5 2 1 9 B51. 15.5 24 5 20 15 1 2 1 7 B51 145 14 2o 15 1 2 1.5 5 B51 15.25 145 20 15 1 2 2 9 B51 18. 42 15 35 2 s 1.5 8 1351 24.25 271 25 5 2 3 1.5 8 B51 24.25 257 17 4 2 2 5 B21 29 455 20 1 5 5 8 B51. 28 425 25 15 1 2 2 11 B51. 22 172 1 Amount of chromium (Cr) in terms of weight percent 1 Amount of cobalt (Co) in terms of weight percent 4 Amount of titanium (Ti) in terms of weight percent Amount of aluminum (Al) in terms of weight percent 5 Amount of tantalum (Ta) in terms of weight percent Amount of columbium (Cb) in terms of weight percent 1 Amount of tungsten (W) in terms of weight percent 8 Amount of zirconium (Zr) in terms of weight percent Amount of boron (B) in terms of weight percent Amount of nickel (N1) in terms of weight percent 11 Equivalent Hardening Factor (E.H.F.)

Rupture Life in hours (R.L.)

It is readily apparent from the above examples and the table that when the equivalent hardening factor of the alloy is below 20, as in Example 16, 17, 18 and 19, the period of time which elapses before rupture is much smaller than is the case when the equivalent hardening factor of the alloy is between about and 30, as in Examples 1 to 15, and 20 to 24.

When the alloys of this invention had an equivalent hardening factor greater than about 30, ingots of such alloys could not be readily hot worked. For example, an ingot comprising by weight about: 20 percent of chromium, 15 percent of cobalt, 3 percent of titanium, 5 percent of aluminum, 3.5 percent of columbium, 8 percent of tungsten, and the balance essentially nickel, having an equivalent hardening factor of 35, broke up and cracked when hot working was attempted. Similar results occurred when an ingot comprising by weight about: 20 percent of chromium, 15 percent of cobalt, 3 percent of titanium, 4 percent of aluminum, 2.5 percent of tantalum, 8 percent of tungsten, and the balance, essentially nickel, having an equivalent hardening factor of 31.75.

I claim:

1. A high temperature, high strength nickel-chromium-cobalt base metal alloy composed by weight of about 15 percent to 25 percent chromium; about 5 percent to percent cobalt; 0.5 percent to 4 percent titanium; 2 percent to 5 percent aluminum; 1 percent to 5 percent of a metal of the class consisting of tantalum, columbium and mixtures thereof; 5 percent to 11 percent tungsten, and the balance, essentially nickel, except for impurities and minor alloying constituents which do not substantially affect the properties of the basic alloy, said alloy being characterized in that the sum of (a) the percentage of tungsten, plus (b) one and one-half times the percentage of the member of said class, plus (1:) two times the percentage of aluminum, plus (d) four times of the class consisting of tantalum, columbium and mixtures thereof; 5 percent to 11 percent tungsten, and the balance, essentially nickel, except for impurities and minor alloying constituents which do not substantially affect the properties of the basic alloy, said alloy being characterized in that the sum of (a) the percentage of tungsten, plus (b) one and one-half times the percentage of the member of said class, plus (c) two times the percentage of aluminum, plus (0.) four times the percentage of titanium equals a number within the range of about 23 to about 28.

3. A high temperature, high strength nickel-chromium-cobalt base metal alloy composed by weight of about 15 percent to 25 percent chromium; 5 percent to 30 percent cobalt; .5 percent to 4 percent titanium; 2 percent to 5 percent aluminum; 1 percent to 5 percent of a metal of the class consisting of tantalum, columbium and mixtures thereof; 5 percent to 11 percent tungsten; the impurities oxygen, nitrogen, hydrogen, lead, iron and carbon not exceeding by weight about .001 percent lead; about .3 percent oxygen; about .05 percent nitrogen, about .001 percent hydrogen, about 5 percent iron, and about 0.5 percent carbon; and the balance, essentially nickel, except for impurities and minor alloying constituents which do not substantially affect the properties of the basic alloy, said alloy being characterized in that the sum of (a) the percentage of tungsten plus (b) one and one-half times the percentage of the member of said class plus (0) two times the percentage of aluminum plus (d) four times the percentage of titanium equals a number within the range of about 20 to about 30.

4. A high temperature, high strength, nickel-chromium-cobalt base metal alloy composed by weight of about 20 percent chromium; 15 percent cobalt; .5 percent to 4 percent titanium; 2 percent to 5 percent aluminum; 1 percent to 5 percent of a metal of the class consisting of tantalum, columbium, and mixtures thereof; percent to 11 percent tungsten, and the balance essentially nickel, except for impuritis and minor alloying constituents which do not substantially aflFect the properties of the basic alloy, said alloy being characterized in that the sum of (a) the percentage of tungsten plus (b) one and one-half times the percentage of the member of said class plus (0) two times the percentage of aluminum plus (d) four times the percentage of titanium equals a number within the range of about 20 to about 30.

5. A high temperature, high strength nickel-chromium-cobalt base metal alloy composed by Weight of about percent to 25 percent chromium; 5 percent to 30 percent cobalt; 0.5 percent to 4 percent titanium; 2 percent to 5 percent aluminum; 1 percent to 5 percent of a metal of the class consisting of tantalum, columbium and mixtures thereof; 5 percent to 11 percent tungsten; a metal of the class consisting of zirconium and boron, the amount of zirconium not exceeding about 0.2 percent and the amount of boron not exceeding about 0.1 percent; and the balance essentially nickel, except for impurities and minor alloying constituents which do not substantially affect the properties of the basic alloy, said alloys being characterized in that the sum of (a) the percentage of tungsten, plus (b) one and one-half times the percentage of a metal of the class consisting of tantalum, columbium and mixtures thereof, plus (0) two times the percentage of aluminum plus (d) four times the percentage of titanium, equals a number within the range of about to about 30.

6. A high temperature, high strength nickel-chromium-cobalt base metal alloy composed by weight of about 15 percent to 25 percent chromium; 5 percent to 30 percent cobalt; 0.5 percent to 4 percent titanium; 2 percent to 5 percent aluminum; 1 percent to 5 percent of a metal of the class consisting of tantalum, columbium and mixtures thereof; 5 percent to 11 percent tungsten; a metal of the class consisting of zirconium and boron, the amount of zirconium not exceeding about 0.2 percent and the amount of boron not exceeding about 0.1 percent; and the balance, essentially nickel, except for impurities and minor alloying constituents which do not substantially affect the properties of the basic alloy, said alloys being characterized in that the sum of (a) the percentage of tungsten, plus (b) one and one-half times the percentage of a metal of the class consisting of tantalum, columbium and mixtures thereof, plus (0) two times the percentage of aluminum, plus (d) four times the percentage of titanium, equals a number within the range of about 23 to about 28.

References Cited in the file of this patent UNITED STATES PATENTS 2,513,471 Franks et a1. July 4, 1950 2,587,275 Bash Feb. 26, 1952 2,842,439 Ebeling July 8, 1958 FOREIGN PATENTS 133,749 Australia Dec. 12, 1946 134,904 Australia Oct. 26, 1949 515,080 Canada July 26, 1955 529,159 Canada Aug. 14, 1956 708,820 Great Britain May 12, 1954 

1. A HIGH TEMPERATURE, HIGH STRENGTH NICKEL-CHROMIUM-COBALT BASE METAL ALLOY COMPOSED BY WEIGHT OF ABOUT 15 PERCENT TO 25 PERCENT CHROMIUM, ABOUT 5 PERCENT TO 30 PERCENT COBALT, 0.5 PERCENT TO 4 PERCENT TITANIUM, 2 PERCENT TO 5 PERCENT ALUMINUM, 1 PERCENT TO 5 PERCENT OF A METAL OF THE CLASS CONSISTING OF TANTALUM, COLUMBIUM AND MIXTURES THEREOF, 5 PERCENT TO 11 PERCENT TUNGSTEN AND THE BALANCE ESSENTIALLY NICKEL, EXCEPT FOR IMPURITIES AND MINOR ALLOYING CONSTITUENTS WHICH DO NOT SUBSTANTIALLY AFFECT THE PROPERTIES OF THE BASIC ALLOY, SAID ALLOY BEING CHARACTERIZED IN THAT THE SUM OF (A) THE PERCENTAGE OF TUNGSTEN, PLUS (B) ONE AND ONE-HALF TIMES THE PERCENTAGE OF THE MEMBER OF SAID CLASS, PLUS (C) TWO TIMES THE PERCENTAGE OF ALUMINUM, PLUS (D) FOUR TIMES THE PERCENTAGE OF TITANIUM EQUALS A NUMBER WITHIN THE RANGE OF ABOUT 20 TO ABOUT
 30. 